The presence of molds in internal environments is not without consequences in terms of health. Indeed, many studies have demonstrated the appearance of symptoms in occupants of premises containing molds, and also their role in the degradation both of the materials and of the structures that they colonize. Indeed, the enzymes and/or the acids produced by the fungi also cause deterioration of their support.
Techniques for detecting the presence of molds in internal environments based on the visual recognition of a fungal development, and the culturing of conidia taken from the air or from surfaces do not make it possible to effectively detect “hidden” contaminations nor to detect contaminations early enough to effectively prevent the deterioration of their supports. Indeed, this deterioration is generally already advanced when the contamination is detectable by visual recognition. Furthermore, the time taken to obtain an answer with these measuring techniques is lengthy since it is necessary to await the growth in the laboratory of the microorganisms sampled before being able to carry out the analysis. Consequently, there is, in particular for certain sensitive fields such as the preservation of artistic or historical works, a demand for a solution which allows early detection and continuous monitoring of fungal contaminations.
As soon as they start to develop, fungi give out volatile molecules (volatile organic compounds, VOCs) resulting either from their metabolism, or from the degradation of the material on which they develop by the enzymes or the acids that they produce. The VOCs diffuse through the walls and can be detected in the air even in the case of hidden contaminations. However, the VOCs present in an internal environment can also come from other sources, such as building materials, household products or alternatively human activity. The concentrations of VOCs of fungal origin, in particular at an early stage of contamination, prove to be relatively low compared with all the VOCs present in an internal environment.
Patent application FR 2913501 proposes a method for detecting a fungal contamination in an internal environment by determining a fungal contamination index based on the analysis of the VOCs present in the ambient air. This method makes it possible to detect a fungal development at an early stage of its development even in the case of a hidden contamination, but uses conventional methods of analysis, such as gas chromatography coupled to mass spectrometry. These methods require the collection of a sample that must be brought back to the laboratory where it will undergo lengthy concentration, separation and analysis steps. These steps for detecting a fungal contamination in an internal environment require the intervention of a qualified technician and prove to be relatively lengthy and expensive. These analysis techniques do not therefore allow a rapid and continuous measurement.
Chemical sensors are commonly used for continuously measuring organic pollutants. However, such sensors are not sufficiently sensitive to detect the concentration levels of VOCs given out during a fungal development, nor sufficiently selective to differentiate these VOCs of fungal origin from the other VOCs originating from other biological sources or from the building materials.
The solutions available to date do not therefore make it possible to meet the demand for early detection and for continuous monitoring of fungal contaminations.